Very minor nitpick but something I couldn't help but notice.
When the "Big Girl" is in uniform she's clearly meant to be depicted as fat or at the very least, fairly hefty. She's almost, if not exactly, the same size as MC.
However when she's in her bikini, she slims down like 10 sizes to match the others. Her proportions match up almost exactly to the other two when she's clearly supposed to be bigger. You can see in the image above that she clearly has bigger legs than the other two by a significant amount yet if you look below they're almost the same size from neck to toe.
Because of this, the roundness of her face doesn't match her body. It seems the original intent was to make her ugly and portly but I guess somewhere along the line he couldn't bring himself to draw a fat chick in a bikini?
Also that's a male face design on her, at least usually. I legitimately had a hard time figuring out if she was girl when I first saw her because I've seen at least 1000 men in manga with that face or similar.
Just weird design decisions I couldn't help but notice. Didn't stop me from enjoying the goofy carnage that came about and it won't stop me from getting giddy when these girls get mauled by an angry mob~